Positron Emission Testing (PET)

What is PET?

Positron Emission Tomography (PET) produces images of molecular-level physiological functioning, which can help physician identify normal and abnormal cell states. As in traditional nuclear medicine, PET uses radio-pharmaceuticals or "tracers," which are labeled with isotopes such as carbon, oxygen, nitrogen and fluorine. These isotopes mimic sugars, water, proteins and oxygen (In our case, FDG, “2-Fluro-2-Deoxy-glucose”). As a result, PET can often reveal more about the cellular-level metabolic status of a disease than the CT or MR. PET can help diagnose a disease often before it shows up on other tests. PET can also show the progress of a disease as well as how the body is responding to treatment.

Current Applications

The three areas in which PET is making critical contributions are:
1. Oncology: lung cancer, breast cancer, testicular and ovarian cancer, recurrent colorectal cancer, lymphoma, melanoma, recurrent brain tumors, tumor-therapy monitoring, and assessing effectiveness of treatments such as chemotherapy.
2. Cardiology: coronary artery disease and myocardial viability.
3. Neurology and psychiatry: Diagnosis of Parkinson's, Alzheimer's, Huntington's, epilepsy, and stroke victims.

How PET Works

PET procedures may vary, but in general, the PET technologist administers the radioisotope by injection to the patient, who lies still for a minimum of 70 minutes, and then is scanned for approximately 30minutes.

What is PET used to diagnose?

PET is used to diagnose and stage patients with cancer, as well as patients with certain brain and heart disorders.

In cancer, PET can:

• distinguish benign from malignant tumors
• stage cancer by showing metastases anywhere in your body
• prove whether or not treatment therapies are working

 In the brain, PET can:

• positively diagnose Alzheimer's disease for early intervention
• locate tumors in the brain and distinguish tumor from scar tissue
• locate the focus of seizures for some patients with epilepsy
• more accurately assess tumor and other sites in the brain for delicate surgery

In the heart, PET can:

• quantify the extent of heart disease
• determine, after a heart attack, if the heart muscle would benefit from surgery

In the bones, PET can:

• Provide the Physician information on the extent, if any, of disease to the skeletal system

Typically a high protein NO carbohydrate diet is ideal 24 hrs prior to the study. Water is encouraged up until actual scan time. FDG is excreted via the urinary system and hydration is necessary for quick renal clearance. An exception to this rule is for a PET Heart study in which a high carbohydrate meal is required prior to the study.

A patient can expect to be in the PET center for one and a half to two hours.

You will feel fine. There are no side-effects from the injected tracer.

The studies are conducted with an injection made up of radioactive glucose (sugar), no side effects have been reported.

A radiopharmaceutical is a radioactive drug. The most commonly used radiopharmaceutical in PET/CT is FDG, which is a radioactive form of glucose. Radiopharmaceuticals are produced by pharmacists and chemists.

Glucose is a common substance that every cell in your body needs in order to function. Diabetic patients need not worry; it would take 1,000,000 doses of FDG to equal the glucose in 1 teaspoon of sugar.

FDG has a half-life of approximately 110 minutes, so it is quickly expelled from your body.

Yes and no. There are examinations that you can have performed. CT and MRI, for example, both examine the anatomical (physical) structure. Therefore, they can be useful in determining the size and location of a tumor; however, neither of them can determine the tumor's viability, whereas PET can determine whether a tumor is still active.  

P.E.T. scans are SAFE and are easily performed
on an out-patient basis in about two hours.

• If you’re female, you should tell your doctor if you are pregnant or think you might be pregnant. Also, you need to tell your doctor if you’re nursing.

• You should not eat anything for 6 hours before the PET/CT Scan. You may drink water only and ABSOLUTELY nothing with sugar or caffeine. It's a good rule of thumb to not eat or drink anything (except water) after midnight.

• On the DAY PRIOR to the exam, you should not eat any foods containing starches or sugars. If you're not sure what foods those are, call Florida Hospital Imaging at (386) 671-4798 and ask for the PET/CT technologist.

• You should wear comfortable clothing for the PET/CT scan. The Center is kept around 70 degrees so some patients will want to bring a jacket or sweater.

• You should tell your doctor if you are diabetic.

• You may wear hearing aids, glasses, and dentures to the Imaging Center but you should leave valuables at home.

• You may take all of your prescribed medications on the day of the scan unless you are told not to. If you are insulin dependent or take Furosemide (Lasix) on a regular basis, please let the technologist know when you arrive at the center.

When you arrive at the center, a small amount of radioactive glucose will be injected into your bloodstream. The material has passed many quality control checks and is very safe, there are no side effects.

Following the injection, you will rest for a minimum of 60 minutes while the glucose mixture is distributed throughout your body. You will then be moved to a table for your pass through the scanner. The whole-body scan will take approximately 20 to 30 minutes and you may be relaxed enough to fall asleep.

There are no side effects from the injected glucose tracer solution. Remember, you haven't eaten for several hours so you may feel weak until you have had a normal meal.

PET scans performed at Florida Hospital Imaging are read by Board Certified Radiologists with specialized training for interpreting images created by the PET/CT